Received 2002-04-17 Accepted
2002-07-01
This work was supported by the National
Natural Science Foundation of
China (No.30170355)
*Corresponding author. Tel: +86-29-3374802;
E-mail: zhanglf@fmmu.edu.cn
四周模拟失重大鼠后身动脉平滑肌细胞钾电流的改变
付兆君, 程宏伟, 张立藩*, 马进
第四军医大学航空航天生理学教研室, 西安 710032
摘要: 本文采用全细胞膜片箝方法观察4-wk尾部悬吊大鼠
(tail-suspended rats, SUS)隐动脉及肠系膜前动脉第2~6级动脉分支血管平滑肌细胞
(vascular smooth muscle cells, VSMCs)钾电流密度的变化。结果表明: SUS大鼠后身动脉VSMCs的静息电位 (RP)较对照大鼠 (CON)后身动脉VSMCs 的RP更负。SUS组隐动脉和肠系膜动脉VSMCs的全细胞钾电流密度较CON组显著增加。其中, SUS组的隐动脉和肠系膜动脉VSMCs的BKCa和KV电流密度较CON组的BKCa和KV电流密度均显著增加。以上结果提示, VSMCs的超极化及进一步引起的通过电压依赖性钙离子通道的钙内流减少可能是模拟失重引起后身动脉反应性降低的电生理机理之一。
关键词: 模拟失重; 膜片箝; 钾离子通道; 血管平滑肌
学科分类号: R852.22
Changes in potassium currents of vascular
smooth muscle cells isolated from hindquarter arteries of 4-wk simulated
weightless rats
FU
Zhao-Jun, CHENG Hong-Wei, ZHANG Li-Fan*, MA Jin
Department
of Aerospace Physiology, Fourth Military Medical University, Xi'an 710032
Abstract: The changes in potassium currents of vascular smooth muscle
cells (VSMCs) isolated from saphenous arteries and the 2nd~6th order branches
of the small mesenteric arteries of 4-wk tail-suspended rats (SUS) were
examined using whole cell patch clamp technique.The resting potential (RP) of
the VSMCs from SUS group was more negative compared with that of the control
group (CON).The whole cell potassium current densities of VSMCs isolated from
the saphenous arteries and small mesenteric arteries in SUS group were
significantly larger than those of the CON group.The BKCa and KV current
densities of VSMCs from saphenous arteries and small mesenteric arteries from
SUS group were also significantly larger than those from the CON group.It is
speculated that the hyperpolarization of VSMCs and decreased calcium influx
through voltage-dependent calcium channels might be among the
electrophysiological mechanisms involved in the depressed vasoreactivity of
hindquarter arteries induced by simulated weightlessness.
Key words: weightlessness simulation; patch-clamp techniques; potassium channels; muscle; smooth; vascular